SqlSingleOperandTypeChecker is an extension of SqlOperandTypeChecker
for implementations which are capable of checking the type of a single
operand in isolation. This isn't meaningful for all type-checking rules (e.g.
SameOperandTypeChecker requires two operands to have matching types, so
checking one in isolation is meaningless).

Method Detail

checkSingleOperandType

Checks the type of a single operand against a particular ordinal position
within a formal operator signature. Note that the actual ordinal position
of the operand being checked may be different from the position
of the formal operand.

For example, when validating the actual call

C(X, Y, Z)

the strategy for validating the operand Z might involve checking its
type against the formal signature OP(W). In this case,
iFormalOperand would be zero, even though the position of Z
within call C is two.

Parameters:

callBinding - description of the call being checked; this is only
provided for context when throwing an exception; the
implementation should NOT examine the
operands of the call as part of the check

operand - the actual operand to be checked

iFormalOperand - the 0-based formal operand ordinal

throwOnFailure - whether to throw an exception if check fails
(otherwise returns false in that case)